We investigate the influence of strain and electric field on the properties of a silicane sheet. Some elastic parameters of silicane, such as an in-plane stiffness of 52.55 N/m and a Poisson’s ratio of 0.24, are obta...We investigate the influence of strain and electric field on the properties of a silicane sheet. Some elastic parameters of silicane, such as an in-plane stiffness of 52.55 N/m and a Poisson’s ratio of 0.24, are obtained by calculating the strain energy. Compared with silicene, silicane is softer because of its relatively weaker Si–Si bonds. The band structure of silicane is tunable by a uniform tensile strain, with the increase of which the band gap decreases monotonously. Moreover, silicane undergoes an indirect–direct gap transition under a small strain, and a semiconductor–metal transition under a large strain. The electric field can change the Si–H bond length of silicane significantly. When a strong field is applied, the H atom at the high potential side becomes desorbed, while the H atom at the low potential side keeps bonded. So an external electric field can help to produce single-side hydrogenated silicene from silicane. We believe this study will be helpful for the application of silicane in the future.展开更多
The adsorption and diffusion behaviors of alkali and alkaline-earth metal atoms on silicane and silicene are both investigated by using a first-principles method within the frame of density functional theory.Silicane ...The adsorption and diffusion behaviors of alkali and alkaline-earth metal atoms on silicane and silicene are both investigated by using a first-principles method within the frame of density functional theory.Silicane is staler against the metal adatoms than silicene.Hydrogenation makes the adsorption energies of various metal atoms considered in our calculations on silicane significantly lower than those on silicene.Similar diffusion energy barriers of alkali metal atoms on silicane and silicene could be observed.However,the diffusion energy barriers of alkali-earth metal atoms on silicane are essentially lower than those on silicene due to the small structural distortion and weak interaction between metal atoms and silicane substrate.Combining the adsorption energy with the diffusion energy barriers,it is found that the clustering would occur when depositing metal atoms on perfect hydrogenated silicene with relative high coverage.In order to avoid forming a metal cluster,we need to remove the hydrogen atoms from the silicane substrate to achieve the defective silicane.Our results are helpful for understanding the interaction between metal atoms and silicene-based two-dimensional materials.展开更多
Hydrogenated two-dimensional(2D)materials have gained significant attention due to their tunable properties,which can be engineered through various functionalization techniques.This review discusses hydrogenated Xenes...Hydrogenated two-dimensional(2D)materials have gained significant attention due to their tunable properties,which can be engineered through various functionalization techniques.This review discusses hydrogenated Xenes,a new class of fully hydrogenated mono-elemental 2D materials,including graphane,germanane,silicane,and stanane.Hydrogenation enhances the properties of Xenes,making them transparent,mechanically strong,electrically conductive,and rare.These materials off er a unique combination of characteristics that make them highly desirable for a variety of advanced applications in energy storage,organic electronics,and optoelectronics.Xenes such as silicane and germanane are semiconductors with tunable bandgaps,making them ideal for use in transistors,logic circuits,and sensors.Their electronic and optical properties can be finely adjusted,allowing them to be used in high-performance devices like LEDs,solar cells,and photodetectors.Furthermore,hydrogenated Xenes show potential in applications like batteries,supercapacitors,hydrogen storage,piezoelectricity,and biosensing,owing to their high surface area and versatility.This review also explores the impact of various hydrogenation techniques,including plasma treatment,wet chemical methods,and electrochemical hydrogenation,on the electronic,mechanical,thermal,optical,and magnetic properties of these materials.Advanced characterization techniques,such as X-ray absorption spectroscopy(XANES),have provided valuable insights into the electronic structure and bonding environments of these materials.Finally,the paper highlights the challenges and limitations of hydrogenation,including structural instability and environmental concerns,while discussing the future prospects and advancements needed to harness the full potential of hydrogenated 2D materials.This review serves as a comprehensive resource for researchers aiming to explore the applications of hydrogenated Xenes in next-generation technologies.展开更多
Surface modification of nanometer titanium dioxide particles and effect of preparing TiO2/P （St-co-DVB） composites by dispersion polymerization are described. To introduce vinyl group onto the surface of titanium di...Surface modification of nanometer titanium dioxide particles and effect of preparing TiO2/P （St-co-DVB） composites by dispersion polymerization are described. To introduce vinyl group onto the surface of titanium dioxide particles, the titanium dioxide particles were surface-modified with a silicane coupling agent, methacryloylpropyltrimethoxysilicane. Polymer encapsulation in the presence of either modified-titanium dioxide particles or unmodified-titanium dioxide particles was carried out by dispersion polymerization of styrene, divinylbenzene in ethanol medium with polyvinylpyrroliclone as stabilizer, and 2, 2＇-azobis（isobutyronitrile） as initiator. The modified-titanium dioxide was analyzed with Fourier-transform infrared spectroscopy（FTIR）, UV-Vis spectrophotometer, thermo-gravimetric analysis and transmission microscope. The polymer encapsulation of modified-titanium dioxide and unmodified-titanium dioxide particles was confirmed with FTIR and transmission electron microscope. Results show that compared with unmodified-titanium dioxide, modified-titanium dioxide is more suitable for preparing inorganic core/orclanic shell composites.展开更多
SiO2 nano particle, through surface modification by silicane coupling agent KH-570, was successfully applied to make nano SiO2/PP composite material by the melt-out blending process with twin-screw extruder. Effects o...SiO2 nano particle, through surface modification by silicane coupling agent KH-570, was successfully applied to make nano SiO2/PP composite material by the melt-out blending process with twin-screw extruder. Effects of nano SiO2on the reinforcing and toughening of PP were studied by analyzing the material impact broken fracture, the crystal structure and the diameter of SiO2nano particle using SEM, XRD and TEM, respectively. Results showed that the impact strength and the tensile strength of nano SiO2/PP composite material were improved apparently; the impact strength of PP was fracture was increased to 67% when the nano SiO2 content was 4%; while the nano SiO2 particle upon surface treatment will impose obvious heterogeneous nucleation function over PP crystal.展开更多
High-entropy(Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2))C ceramics,with different contents(0,5,10,and 20 vol.%)of Si C whiskers(SiCw),were fabricated by spark plasma sintering using raw powders synthesized via carbother...High-entropy(Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2))C ceramics,with different contents(0,5,10,and 20 vol.%)of Si C whiskers(SiCw),were fabricated by spark plasma sintering using raw powders synthesized via carbothermal reduction.The application of a uniaxial compaction force led to texture development of the SiCw within the(Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2))C matrix.Fracture toughness increased with the increase in SiCw content,while Vickers hardness remains almost unchanged.The toughness of(Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2))C-20 vol.%SiCw ceramics reached 4.3±0.3 MPa m^(1/2),which was approximately 43%higher than that of the monolithic(Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2))C ceramic(3.0±0.2 MPa m1/2).The main toughening mechanisms were attributed to crack deflection,whisker debonding,and whisker pullout.展开更多
基金Project supported by the National Natural Science Foundation of China (Grant No. 60925016)
文摘We investigate the influence of strain and electric field on the properties of a silicane sheet. Some elastic parameters of silicane, such as an in-plane stiffness of 52.55 N/m and a Poisson’s ratio of 0.24, are obtained by calculating the strain energy. Compared with silicene, silicane is softer because of its relatively weaker Si–Si bonds. The band structure of silicane is tunable by a uniform tensile strain, with the increase of which the band gap decreases monotonously. Moreover, silicane undergoes an indirect–direct gap transition under a small strain, and a semiconductor–metal transition under a large strain. The electric field can change the Si–H bond length of silicane significantly. When a strong field is applied, the H atom at the high potential side becomes desorbed, while the H atom at the low potential side keeps bonded. So an external electric field can help to produce single-side hydrogenated silicene from silicane. We believe this study will be helpful for the application of silicane in the future.
基金Project supported by the Natural Science Foundation of Jiangxi Province,China(Grant Nos.20152ACB21014,20151BAB202006,and 20142BAB212002)the Fund from the Jiangxi Provincial Educational Committee,China(Grant No.GJJ14254)supported by the Oversea Returned Project from the Ministry of Education,China
文摘The adsorption and diffusion behaviors of alkali and alkaline-earth metal atoms on silicane and silicene are both investigated by using a first-principles method within the frame of density functional theory.Silicane is staler against the metal adatoms than silicene.Hydrogenation makes the adsorption energies of various metal atoms considered in our calculations on silicane significantly lower than those on silicene.Similar diffusion energy barriers of alkali metal atoms on silicane and silicene could be observed.However,the diffusion energy barriers of alkali-earth metal atoms on silicane are essentially lower than those on silicene due to the small structural distortion and weak interaction between metal atoms and silicane substrate.Combining the adsorption energy with the diffusion energy barriers,it is found that the clustering would occur when depositing metal atoms on perfect hydrogenated silicene with relative high coverage.In order to avoid forming a metal cluster,we need to remove the hydrogen atoms from the silicane substrate to achieve the defective silicane.Our results are helpful for understanding the interaction between metal atoms and silicene-based two-dimensional materials.
基金partially supported by the financial supports from Aaivalayam-DIRAC,Indiathe Science and Technology Development Fund(Nos.007/2017/A1 and 132/2017/A3),Macao Special Administration Region(SAR),China+2 种基金National Natural Science Fund(Nos.61875138,61435010,and 6181101252)Science and Technology Innovation Commission of the Shenzhen(Nos.KQTD2015032416270,JCYJ20150625103619275,and JCYJ20170811093453105)research funding from the Ministry of Science and Higher Education of the Russian Federation(Ural Federal University project within the Priority 2030 Program)。
文摘Hydrogenated two-dimensional(2D)materials have gained significant attention due to their tunable properties,which can be engineered through various functionalization techniques.This review discusses hydrogenated Xenes,a new class of fully hydrogenated mono-elemental 2D materials,including graphane,germanane,silicane,and stanane.Hydrogenation enhances the properties of Xenes,making them transparent,mechanically strong,electrically conductive,and rare.These materials off er a unique combination of characteristics that make them highly desirable for a variety of advanced applications in energy storage,organic electronics,and optoelectronics.Xenes such as silicane and germanane are semiconductors with tunable bandgaps,making them ideal for use in transistors,logic circuits,and sensors.Their electronic and optical properties can be finely adjusted,allowing them to be used in high-performance devices like LEDs,solar cells,and photodetectors.Furthermore,hydrogenated Xenes show potential in applications like batteries,supercapacitors,hydrogen storage,piezoelectricity,and biosensing,owing to their high surface area and versatility.This review also explores the impact of various hydrogenation techniques,including plasma treatment,wet chemical methods,and electrochemical hydrogenation,on the electronic,mechanical,thermal,optical,and magnetic properties of these materials.Advanced characterization techniques,such as X-ray absorption spectroscopy(XANES),have provided valuable insights into the electronic structure and bonding environments of these materials.Finally,the paper highlights the challenges and limitations of hydrogenation,including structural instability and environmental concerns,while discussing the future prospects and advancements needed to harness the full potential of hydrogenated 2D materials.This review serves as a comprehensive resource for researchers aiming to explore the applications of hydrogenated Xenes in next-generation technologies.
基金Supported by National High Technology Research and Development Program of China (863 Program) (No. 2004AA302010) and Natural Science Foundation of Tianjin (No. 043186411) .
文摘Surface modification of nanometer titanium dioxide particles and effect of preparing TiO2/P （St-co-DVB） composites by dispersion polymerization are described. To introduce vinyl group onto the surface of titanium dioxide particles, the titanium dioxide particles were surface-modified with a silicane coupling agent, methacryloylpropyltrimethoxysilicane. Polymer encapsulation in the presence of either modified-titanium dioxide particles or unmodified-titanium dioxide particles was carried out by dispersion polymerization of styrene, divinylbenzene in ethanol medium with polyvinylpyrroliclone as stabilizer, and 2, 2＇-azobis（isobutyronitrile） as initiator. The modified-titanium dioxide was analyzed with Fourier-transform infrared spectroscopy（FTIR）, UV-Vis spectrophotometer, thermo-gravimetric analysis and transmission microscope. The polymer encapsulation of modified-titanium dioxide and unmodified-titanium dioxide particles was confirmed with FTIR and transmission electron microscope. Results show that compared with unmodified-titanium dioxide, modified-titanium dioxide is more suitable for preparing inorganic core/orclanic shell composites.
文摘SiO2 nano particle, through surface modification by silicane coupling agent KH-570, was successfully applied to make nano SiO2/PP composite material by the melt-out blending process with twin-screw extruder. Effects of nano SiO2on the reinforcing and toughening of PP were studied by analyzing the material impact broken fracture, the crystal structure and the diameter of SiO2nano particle using SEM, XRD and TEM, respectively. Results showed that the impact strength and the tensile strength of nano SiO2/PP composite material were improved apparently; the impact strength of PP was fracture was increased to 67% when the nano SiO2 content was 4%; while the nano SiO2 particle upon surface treatment will impose obvious heterogeneous nucleation function over PP crystal.
基金financially supported by the National Natural Science Foundation of China(Nos.51832002,51402055,51602060,U1401247)the Science and Technology Program of Guangzhou(No.201704030095)。
文摘High-entropy(Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2))C ceramics,with different contents(0,5,10,and 20 vol.%)of Si C whiskers(SiCw),were fabricated by spark plasma sintering using raw powders synthesized via carbothermal reduction.The application of a uniaxial compaction force led to texture development of the SiCw within the(Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2))C matrix.Fracture toughness increased with the increase in SiCw content,while Vickers hardness remains almost unchanged.The toughness of(Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2))C-20 vol.%SiCw ceramics reached 4.3±0.3 MPa m^(1/2),which was approximately 43%higher than that of the monolithic(Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2))C ceramic(3.0±0.2 MPa m1/2).The main toughening mechanisms were attributed to crack deflection,whisker debonding,and whisker pullout.
